SOLplus - Improved Energy Efficiency of Solar PV Systems via Low Surface Energy Coatings

Recent reports indicate that a significant impact of accumulation of dust and other debris on the surface of photovoltaic modules causes a decrease in the incoming solar irradiance, with typical power losses of 10-15%, or even up to 50% in some cases reported. Durable highly repellent coatings based on advanced, nanostructured, low energy materials can provide a permanent solution to prevent the accumulation of dirt on the transparent top layer of a PV system. The primary objective of the SOLplus project is to determine the technological, commercial, and economic viability of such a low surface energy coating for use in the solar PV market. The main technology and commercial objectives for this product will be to deliver a durable coating that prevents the accumulation of dirt/dust on glass and plastic solar substrates, is cost-effective in its application method, and demonstrates real and tangible benefits to the end user (maintenance-free and avoidance of expensive cleaning procedures). Technology validation for the solar PV market and a refinement of our assessment of the market opportunity during the project will allow for a better focus on the market needs

IMPACT SUMMARY

The market for solar modules has increased by 35% pa compound over the past 15 years. There are several drivers that account for this extraordinary growth including increasing energy demand, security of supply of fossil fuels as well as concerns over global warming and climate change. The industry produced 49GW of photovoltaic modules in 2014 and is forecast to reach an output of 100GW by 2018.

The accumulation of dust and other debris on the surface of photovoltaic modules leads to a significant loss in the absorbed solar irradiance and lower power output. Losses can be 10-15%, or even up to 50% in some cases . Durable, highly repellent coatings based on advanced, nanostructured, low energy materials can provide a solution to prevent the accumulation of dirt on the transparent top layer of a PV system. The primary objective of the SOLplus project is to determine the technological, commercial, and economic viability of such a low surface energy coating for use in solar PV. CREST at Loughborough University is well placed to assist the development. The research team at CREST has developed broadband anti-reflection (AR) coatings that increase the light absorbed in the devices and hence increase the photocurrent by ~4%. It is essential that the broadband AR is treated with a super-hydrophobic coating to revent soiling that would otherwise negate the AR effect. A low energy coating is beneficial on solar cover glass even without the addition of an AR coating.

The collaborators in this project are the immediate beneficiaries. The Solar Cloth Company is an End User able to define performance and durability objectives. An anti-soiling coating on its flexible photovoltaics on structural fabrics will drastically reduce the cost of maintenance of deploying its power producing product over local authority car parks. Cornelius Specialities Ltd is a specialist coatings company capable of developing surface coatings chemistry while Opus Materials Technologies Ltd., has the marketing expertise to address and grow the market. TWI has deep knowledge of
hydrophobic coating technology and CREST has the analytical capability to measure overall performance and durability. This consortium contains the mix of skills required to deliver and exploit this multidisciplinary project. It also represents a UK supply chain capable of delivering the technology and also capable of addressing the world-wide market.

CREST will ensure that IP protection has been obtained prior to any public disclosure. CREST is in an excellent position to disseminate the results of the project. Loughborough University leads the EPSRC SuperSolar Hub which now has almost
500 Network members. Professor Walls is the Director of the Hub and Principal Investigator on this project. The Hub organizes events which provide venues for dissemination and networking in the UK. Walls is also a member of the Solar Energy Special Interest Group (SESSIG) which encourages industrial development in solar energy. He is also a member of the DECC UK PV strategy group and co-chair of DECC's Task force on PV Innovation.

The CREST team attend the IEEE Specialist Photovoltaics Conference (PVSC). This is an important PV forum attracting prominent researchers from research Institutions and Industrial R&D organisations. It is the perfect venue for dissemination and often leads to the development of commercial opportunities. Walls is a member of the International Advisory Board for the IEEE PVSC. CREST has established important relationships with the National Renewable Energy Laboratory (NREL) which has connections with PV module manufacturers worldwide. The link that CREST has developed with NREL will be
useful to its industrial partners both technically and commercially. The commercial exploitation of the project outcomes will be the responsibility of the three industrial partners. CREST will assist this activity through its worldwide network of contacts.